Bendable genes of warm-blooded vertebrates

Area of Science:

• Genomics
• Molecular Biology
• Biophysics

Background:

• GC-content, the proportion of guanine and cytosine bases, influences DNA structure and function.
• DNA bendability and melting energy are critical biophysical properties affecting DNA processes.
• Previous research indicates variations in DNA composition across different organisms.

Purpose of the Study:

• To investigate the relationship between GC-content and DNA helix bendability in warm-blooded vertebrates.
• To compare these relationships in exons and introns, and across different organism types.
• To explore the potential role of selection in GC-enrichment based on DNA bendability.

Main Methods:

• Comparative genomic analysis of DNA sequences from various vertebrates.
• Calculation of DNA bendability and free energy of melting (delta G) based on GC-content.
• Statistical analysis to assess correlations and trends.

Main Results:

• Increased GC-content correlates with higher DNA helix bendability in warm-blooded vertebrates, notably in introns.
• Exons and introns show increased melting energy with higher GC-content, but decrease relative to random sequences.
• These GC-content-related trends are less consistent in cold-blooded animals, plants, and unicellular organisms.
• A negative correlation exists between bendability and melting energy at fixed GC-content, stronger in introns.

Conclusions:

• GC-enrichment in homeotherm vertebrate genes may be driven by selection for increased DNA bendability.
• DNA flexibility appears to be a significant factor shaped by evolutionary pressures in warm-blooded animals.
• Introns exhibit distinct biophysical properties related to GC-content compared to exons.